Low temperature tar conversion to high temperature tar in high temperature coking chambers



July 24, 1956 J. BECKER Low TEMPERATURE TAR CONVERSION To HIGH TEMPERATURE TAR IN HIGH TEMPERATURE COKING CHAMBERS Filed may 4, 1954 uvwnl u# #EE-s# 95.8 25.525... zu;

, Y. .R m M E we r P u Q H w yf yUnite States Patent LOW TEMPERATURE TAR CONVERSION TO HIGH TElVIPERATURE TAR IN HIGH TEMPERATURE COKING CHAMBERS Joseph Becker, Pittsburgh, Pa., assignor to Koppers Company, Inc., a corporation of Delaware Application May 4, 1954, Serial No. 427,675

9 Claims. (Cl. 20223) produce relatively large volumes of low temperature tar which comprise a mixture of paraflinic, olenic, and aromatic hydrocarbons, together With relatively large percentages of polyhydric phenols. Unlike high temperature tar, which has components almost entirely aromatic in nature with the phenol content almost entirely monohydric, the components of low temperature tar are more diicult to separate. As a result, no ready markets for low temperature tar have been found in the United States at an attractive price. Moreover, the components of low temperature tar are considerably less valuable than the components of high temperature tar, no ready market existing in the United States for low temperature tar components, except for their use as fuel whereas the demand for the high temperature tar often exceeds the amount that can be produced in converting coal to high temperature coke without exceeding the demand for the high temperature coal coke from which the high temperature tar must be derived.

The `present invention provides a process of effectively utilizing this waste product low temperature tar by eficiently converting it to the high temperature tar which is more aromatic in nature and is therefore readily separable into desirable components by distillation in the same conventional tar `distilling equipment employed for the tar of high temperature coke ovens.

More particularly, the present invention provides a process for the utilization of low temperature tar from low temperature coking processes comprising the steps of mixing low temperature tar aforesaid with a coal charge, preferably a coal charge suitable for high temperature coking, and subjecting the mixture to high temperature coking in high temperature coking chambers, the volatile portion of the low temperature tar being thereby recovered therefrom in the form of high temperature tar.

In addition, currently the aim is to produce low temperature coke and other carbon residues as char for addition to high volatile coal destined for high temperature coking in common and conventional chamber ovens for producing gas and coke for metallurgical furnaces. It has not been possible to attain this in a sufficiently economical way as is essential for practical use of char manufacture for this end or purpose, since the cost of producing such char as the additive exceeds the value attained by such use of it as the additive. The low temperature tar being deemed a Waste product, for the above noted reasons, cannot be used as a credit, or processed in the same equipment used to process the tar from the high temperature coking operation, and so the aim has been to produce the char in such a rudimentary manner that the cost of production will be low enough to warrant use of the char as an additive without benefit of the low temperature tar. This discourages better manufacture of the char, and the tar must still be disposed of as a waste product.

Further, the present invention provides for this purpose a process wherein all the low temperature tar produced by low temperature carbonization is efficiently utilized, along with all of the char that is also produced thereby, as an addition in such a high temperature coking chamber system, by mixing the char and low temperature tar with a charge of coal suitable for high temperature coking and subjecting the mixture to high temperature coking in coking chambers of the horizontal, intermittent vertical, or inclined type.

It will be obvious to one skilled in the art to which this invention appertains that various changes can be made in the several steps of the process disclosed hereinafter without departing from the scope or spirit of this invention.

On the drawing is illustrated in Fig. 1 a ow diagram of the steps of the preferred embodiment of the invention with horizontal coking chambers. Figs. 2 and 3 show diagrammatically an intermittent vertical and an inclined oven chamber which may be used equivalently.

In carrying out the present invention, the low temperature tar, which can be produced in any of a number of known low temperature coking processes as illustrated diagrammatically in system 10 operating in the temperature range of approximately 450 C. to approximately 700 C., and having a char discharge 11 and hopper 12, with gas oiftakes 13, 14, and `decanter line 15, is mixed with a quantity of coal suitable for high temperature coking in chambers 16.

In a preferred embodiment, the low temperature tar from decanter line 15 and the coal for high temperature coking in 19 are mixed in the range of from approximately 1% to approximately 10% tar to approximately 99% to approximately coal by weight.

The mixing is advantageously accomplished outside the high temperature coking chambers illustrated at 16 with a horizontal chamber, and 16a for an intermittent and 1Gb for an inclined chamber type of high temperature coking oven. These coking chambers can be of the horizontal, vertical or inclined type. Examples of these types are illustrated in, for instance, Becker Patent 2,498,784, Becker Patent 1,779,958, and Becker Patent 1,606,140. It is to be understood that in some instances the mixing can be accomplished as at 17 prior to the final crushing of the coal in the hammer mill 20. It is to be further understood that the coal in 19 with which the low temperature tar from 17 is mixed can be of a high volatile type or it can be a blend of a number of types of coals forming a coal mixture suitable for high temperature coking.

The low temperature tar in 17 can be mixed With char from 18, such as that derived at 12 from low temperature coking in 10 together with a charge of coal from 19 preferably one suitable for high temperature coking and the mixture subjected to an intermittent high temperature coking in the temperature range of from approximately 800 C. to approximately 1150 C. in the oven charnbers 16.

As an example of carrying out the present invention, 285 tons of coal are charged to low temperature coking apparatus 10 which is operated in normal manner. As a result of the low temperature coking, 200 tons of char and 36 tons of low temperature tar are produced. This char in 18 and tar in 17 is then mixed with 800 tons of high volatile coal from 19 destined for and subjected to high temperature coking in chamber ovens 16 as aforesaid, that is, in horizontal, vertical, or inclined chamber ovens. As a result, the yield of high temperature tar is increased over that produced from the same charge of coal alone in 16 by an amount corresponding to about one-half the weight of the low temperature tar charged, without increasing the coal coke yield of 16, and -tlie'reduction invalue of the coal, coke capacity is more than Offset, by the increase in value` oli the converted low. tempartiture tar waste product` to, the more yaxluable high temperature tar of greater demand.` This has the effect l of also` finally, converting the` une:o nornical` low temperattire colte system to the long desired one ot suicient economy and. practical enough to. Warrant conjunctive use for low temperature additives tol high. temperature cohngchamber systems.

rlhis process `eliminates the requirement for the` usual special distillation equipment fonhandling. the low. tempera'ture tar from,lipef1S.,` asl distinguishedlfrom high temperature tar from. 21,' since thek resulting `high temperature tar from the low temperature tar in line 15, canbe handled in' existing conventional tar, distillation equipment for high temper c tire `tar through line 21.- Thus, a substantial, savings' can be made in, investment costs-forA tar distillation andV handling equipment, and, in addition, low temperature.

tars: canY be, converted into high temperature tars, having a tayorab market future` l The invention claimed is:

l. A process for the utilization of low. temperature tar comprisingthe` steps of mixing. said low temperature tar with aq coal destined for high, temperature coking atA a tei'npera'tnrreA aboye 890? C. in high temperature coking cbarinbeijszand subjecting said mixture to high temperature coitingA in high temperature chamber ovens', andrecoveiing` `the` volatile portionof` said low temperature tarh in the iorm of high temperature tar from said chamber` ovens in mixturewith` the high temperature tar givenoi at4 the Sametime therein from the coking of the coal therein, thereby increasing the high temperature tar yield, of saidZ chambers withoutv substantially increasing the coal Coke yield ofsaidgchambers.

2. The process of claim` 1, wherein said, coaLcharge and` said low temperaturetar are in` the prOPQItionsrof approximately NZS-10%k low temperaturetar tofflppi'oxi-` matelyl 9v9l%-90,% coal charge by Weight.

3, The process of claim` 1,I`sa id high temperature coking; being carried on in h'orizvontal coking chambers.

4.l T he process ofl claim 1, said,hightemperaturelcoking being carried on in in clinedcoking.chambers.

5. Theprocess of claim 1said high temperature coking 4 being` carriedy onin` vertical coking, chambers.

6` The process of c1aim-5,lsaid vertical cokng chambersbeingof the intermittent type.

7. A process for the utilization of low temperature tar comprising mixing said low temperature tar with Char and coal destined for high temperature coking at a temperature above 800 C. in high temperature coking chambers and subjecting said mixture to high temperature colting in high temperature chamber ovens, and recovering the volatile portion of said low temperature tar in the form` of high `temperature tar from said chamber ovens `in mix-turerwith the high temperature tar given oi atthe same time therein from the coking of the coal therein, therebyt increasing the high templature, tar yield, of said chambersk without substantiallyv increasing" the coal coke yield of said chambers.

8. A- process for the utilization of low temperature tar comprising subjecting a coal charge to low temperatnre cohing to produce products including char and low temperature tar, mixing said char and said low temperature tar with a` second coal charge destined for high tempeiaturecoking at a temperature above 800. C. in high temperature coking chambers and subjecting said mixture to high temperature coltingin` hightemperature` chamber ovens, and recoyering the volatile portion of said low temperature tar iny the form of high temperature tan from said chamber ovensin mixture with the high temperature tarl givenV ofi at thesame time therein from the colting of the coal therein, thereby increasing the high` temperature tan yieldl of said chambers without substantially increasing the lcoalcoke yield of said chambers.

9. The` process of claim 8, wherein4 said second` coal charge and said char, and tar are. in the proportions of approximately 90%-70% second coal charge toapproximately 10%.30% char and tarfby weight.

References Citedy in theile of this patent UNTTED STATES PATENTS 100,42v McKenzie Mar. l, 1870 175,744; Benrose et al. Apr. 4; 1876 1,311,810 Sperr Dec. l, 1925 1&54-,866` Egloff Apr. 17, 1934` 2,177,226 Rice etral Oct. 24, 1939 OTHER REFERENCES Chemistry ofCoal Utilization, by H, Lowry (John Wi1ey,&.So11$,y l945),lvol. 2, pp.,128,71370.

Low Temperature Carbonisation, by Wellington and Cooper; (GrinCo, yLondon-1924), pp. 48, 7585 incl.

CoaL Carbonizationff byy John Roberts (Pitman e Sons) London, 1927. 

1. A PROCESSS FOR THE UTILIZATION OF LOW TEMPERATURE TAR COMPRISING THE STEPS OF MIXING SAID LOW TEMPERATURE TAR WITH A COAL DESTINED FOR HIGH TEMPERATURE COKING AT A TEMPERATURE ABOVE 800* C. IN HIGH TEMPERATURE COKING CHAMBERS AND SUBJECTING SAID MIXTURE TO HIGH TEMPERATURE COKING IN HIGH TEMPERATURE CHAMBER OVENS, AND RECOVERING THE VOLATILE PORTION OF SAID LOW TEMPERATURE TAR IN THE FORM OF THE HIGH TEMPERATURE TAR FROM SAID CHAMBER OVENS IN MIXTURE WITH THE HIGH TEMPERTURE TAR GIVEN OF AT THE SAME TIME THEREIN FROM THE COKING OF THE COAL THEREIN, THEREBY INCREASING THE HIGH TEMPERATURE TAR YIELD OF SAID CHAMBERS WITHOUT SUBSTANTILLY INCREASING THE COAL COKE YIELD OF SAID CHAMBERS. 